1. Field of Invention
The invention relates to multiple nozzle arrays, and particularly to a method for making multiple nozzle wafers for use in ink jet recording.
2. Description of the Prior Art
The fabrication of glass tubes with very small openings is known in the art. For example, U.S. Pat. No. 3,294,504 to John W. Hicks, Jr., which issued on Dec. 27, 1966, discloses the manufacture of glass fibers by assembling as many as ten thousand glass tubes 0.010 inch in diameter and one foot long into a bundle about one inch in diameter, which are fused into a composite assembly and sliced into wafers. U.S. Pat. No. 3,216,807 to Richard F. Woodcock, which issued on Nov. 9, 1965, discloses a process for fabricating fiber optical devices wherein the fiber optic elements are placed in a grooved block which serves as an alignment means.
Also known in the art is a method for making nozzles used in ink jet recording. For example, U.S. Pat. No. 3,662,399 to Takao Yanoi, which issued on May 9, 1972, discloses the fabrication of such a nozzle which comprises a glass capillary over which a silicone coating is deposited. The coated capillary is then sliced to obtain a nozzle of desired length.
Reference may also be made to a pending application entitled "Pre-Aimed Nozzle for Ink Jet Recorder and Method of Manufacture," Ser. No. 544087, filed Jan. 27, 1975, now abandoned to D. F. Jensen, et al. (EN9-74-021). There is disclosed the potting of a tube in a groove of a wafer block with soldered glass and the cutting of the block along planes perpendicular to the external location surfaces to obtain tubes precisely aimed relative to the wafer body.
Another pending application, "An Apparatus and a Method for Fabricating Precision Tubing and Ink Jet Nozzles," Ser. No. 573,233, filed Apr. 30, 1975, now abandoned to A. R. Hoffman et al. (Y09-73-076), discloses a method and an apparatus for the batch fabrication of ink jet nozzles in which high pressure ink nozzles are fabricated by carefully controlled drawing of glass tubing.
It is also known how to slot plates with precision and to convert plate assemblies into usable nozzle wafers. For example, U.S. Pat. No. 3,674,004 to Johannes Grandia et al., which issued on July 4, 1972, describes a precision cutting apparatus. The IBM Technical Disclosure Bulletin, Vol. 17, No. 7, Dec. 1974, p. 2171, discloses a precision lapping and polishing apparatus.
In ink jet recorders, liquid ink is supplied under pressure to a nozzle having a very small opening through which extremely fine, continuous jet of ink is projected. It has become recognized that the proper operation of such recorders very much depends upon the manner in which the nozzle is sealed to its surrounding surface. The area in the vicinity of the nozzle must be void-free and bubble-free to prevent leaking or breaking when the nozzle, in thin wafer form, is subjected to fluid pressure. Furthermore, the sealing operation must be performed in such a way as not to alter the nozzle in size or shape. Also, the sealing operation must be performed in such a way as not to alter the previously sealed surfaces. Thermal expansion curves of the fabricating elements must be carefully considered to prevent excessive stresses and/or cracking of any of the elements, especially when they are cut into thin wafers, then lapped and polished for use in ink jet recorders. None of the methods described in the above prior art provide a nozzle seal of this high quality.
The use of multiple glass nozzles sealed in accordance with this invention meets all the requirements of nozzle-per-spot technology in ink jet recording. By providing parallel sealed glass nozzles of uniform size and area, velocity uniformity, break-off uniformity, directional uniformity and directional stability are achieved. Drilling holes in a block of ceramic or other material cannot provide such identical holes to meet all these requirements. Furthermore, it has been found that glass provides better nozzle size and area uniformity than silicon. Glass nozzles provide less wandering of fluid streams, that is, about 0.5-1.0 milliradians compared to some 3-8 milliradians for other kinds of nozzles. Locating such glass tubes side-by-side improves hole alignment uniformity, that is, about 0.1 mil in 2 inches compared to 3 mils in 2 inches for other kinds of nozzles.